crownfield



D. CROWNFIELD.

LIGHTING FIXTURE.

APPucATloN FILED 1uNz17. 1915.

D. CROWNFIELD.

LIGHTING FIXTURE.

APPLICATION man IuNE u. 1915.

2 SHEETS-SHEET 2.

Patented Aug. 8

M i Manned/.

DAVID CBOWNFIELD, 0F CAIIBBIIDGE, MASSACHUSETTS.

LIGHTING-FIXTURE.

Specification of Letters Patent.

Patented Aug. 8, 1916.

Application led J'iine 17, 1915. Serial No. 34,720.

To all whom it may concern: l

Be it known that I, DAVID CiiowNrIEin, a citizen of the United States, and resident of Cambridge, in the county of Middlesex and State ofv Massachusetts, have invented new and useful Improvements in Lighting- Fixtures, of which the following is a specification.

This invention relates to a l hting fixture, and particularly to a lighting fixture for use in an apartment where under certain conditions a general distribution of light is required, and under other conditions a concentration of the light is desired within a limited zone.

While susceptible of more general use the fixture is primarily designed for use in operating rooms of hospitals, where one or more of the fixtures may be hung above or around an operating table, and may be so adjusted as to afford a general illumination of the room, or a more concentrated and powerful illumination of a limited area at and about the operating table, as desired. The device also permits a hospital operating table to' be powerfully lighted without the suspension of a fixture immediately over or too close to the operating table, and so avoids the harmful concentration of heat rays upon the patient. It also permits, by its ide range of adjustability, a varied concentration and distribution of light, so that Y it is not necessary to place the light directly over the patient, and thus avoids the danger of septic poisoning or infection which is sometimes caused by the falling of dust particles or the like. The adjustability of the g fixture for a wide distribution of light also makes it adaptable for use in autopsy rooms as well as operating rooms, where a less concentrated light is required, or where more than one subject may be under consideration at the same time. The fixture is also adapted for use under other conditions, wherever it is desired to distribute artificial light over variable areas.

The adjusting connections, and the joints or couplings lby which the several parts are connected, are also arranged wholly interior to the outer shells or casings, and the latter present smooth, practically continuous, rolling surfaces, free from exterior fastening devices or other projections, on which dust and dirt might lodge and become a source of danger to the user, or disiiguremellt to the fixture.

These and other features will hereinafter be more particularly described and pointed out in the claims. AIn the .accompanying drawings which illustrate one embodiment of the invention, Figure 1 is a side elevation, partly in section, showing the fixture as a whole; Fig. 2 is a longitudinal section, partly broken away, of the shades, their connections and associated parts; Fig. 3 is a detail in longitudinal section of the canopy and its associated parts; Fig. 4 is a perspective view, partly broken away, showing said canopy unfastened; Figs. 5 and 6 are per spectiye views of two interlocking supporting rings for the main adjustable shade; Figs. 7 and 8 are perspective views of gripping and supporting members for the inner shade or dust cover; and Fig. 9 is a plan view, partly broken away, illustrating the parts shown in Figs. 7 and 8.

Referring to the drawings, 1 represents the outer tube or casin and 2 the inner pipe of the stem by which the fixture as a whole is 'suspended from the ceiling C. The pipe 2 is fastened (Fig. 3) to an ordinary junction box 3 in the ceiling, through an ordinary hickey joint 4 and an ordinary insulating joint 5. The outer casing 1 may be of brass tubing or other material adapted to produce a handsome finish, and is fastened to the pipe 2 by a set screw 6.

The connections between the stem and the ceiling are inclosed by a canopy 7, consisting of a funnel-like shell, to the interior of which is secured a diaphragm 8 provided with notches 9 (Fig. 4) in its inner margin. A collar 10 is adj ustably Secured t0 the stem 1 within the canopy by means of set screws 11, and the canopy is held in place against the ceiling by said set screws and diaphragm, by pushing the canopy upward until the set screws 11 pass through notches 9, whereupon the canopy is given a slight turn until the diaphragm rests on the heads of the set screws.

The main adjustable shade 12 is carried by a shade supporting shell 13, to the upper end of which is secured a bearing ring 14 which slides up and down the stem 1. A sleeve or tube 15, exteriorly screw threaded, is fastened to the lower end of the stem by means of a screw 16. A nut 17 is threaded on to sleeve 15, and is secured to the interior of the shade supporting shell 13 by means of an inner shell 18.

` the inner ring from bein By turning the shade supporting shell 13 on the stem, the shell 13 and its shade 12 ma be screwed up and down on the stem an adjusted to the desired height; and the adjusting connections are wholly interior to the shell- 13.

The shade 12 is also connected to the supporting shell 13 b means wholly interior to the shell. The s ell 13 is provided at its lower, flaring end with an lnturned lip 19 which engages and supports a ring 20. The ring .i0 is angular in cross section, and its laterally extending flange is provided with a series of notches'21. Projections or spurs 22 are formed at the sides of said notches, one being preferably longer than the other, for the purpose hereinafter explained. An inner coupling ring" 23 is secured by set screws 24 to a suitable lip at the top of shade 12, and is provided with a series of ears or projections 25, corresponding to notches 21. The ring 23, secured to the shade, is passed upward into ring 20 until the ears 25 pass through notches 21, and then is given a slight turn until the ears pass over the to of the shorter projections 22, whereupon t e ears 25 will rest upon the lateral flange of ring 20 and support the shade at the lower end of shell 13. The longer projections 22 act as stops to prevent turned too far, while the shorter projectlons 22, although permitting the ears to pass over them when the parts are being assembled, act as stops to prevent the accidental dislodgment of the ears from the outer ring, in case the inner ring should be turned in reverse direction by jarring or other accidental circumstance.

At the lower extremity of the stem, below adjusting nut 17, is the nozzle 26, tapped and threaded to receive the ends of pipe 2, casing 1 and sleeve 15. The set screw 16 which connects 1 and 2 also passes through nozzle 26. A nipple 27 is threaded into the lower end of nozzle 26 and supports the lamp socket 28, and a yoke holder 29, the

latter consisting of a shell surrounding the end of the lamp socket and held in place by a nut 30 screwed on to nipple 27. 1 The nozzle 26 is of reduced diameter at about its middle and is exteriorly screw threaded to take the nut 31, which supports the shell 32. The nut 31 also supports the heat deflector 33, extending across the opening at the center of shade 12 and excluding hot air which would otherwise rise into the shell 13, carrying with it dust and dirt, and also possibly injuring the insulated wiring which passes through the stem, The shell 32 is provided with air vents 34 in its upper part to permit the escape of hot air. The lower part of the shell 32 is made with a series of slots forming a plurality of flexible fingers 35, the ends of which are bent inwardly to engage a lip at the top of a dust cover or protective shade 36. Said fingers may be sprung over the lip of shade 36 and are held in engagement therewith by a skirt or clamping band 37 which fits outside of the shell 32 and when moved downward over fingers 35 locks them in engagement with shade 36. The skirt 37 may be turned on shell 32 by means of a projection 38, and is locked in operative position over fingers 35 by projections 39 on shell 32, which pass through slots 4() and engage the upper edge of skirt 37.

A glass bowl or diffusing shade 41 is su ported below the lamp L by means of a yo e or skeleton frame 42, comprising a series of ribs, the upper ends of which are connected to the yoke holder 29. The yoke 42 also has a button nipple 43 at its lower extremity, which passes through a hole in bowl 41 and has a head 44 to support the bowl. The nipple is held in place on the bowl by a fastening and adjusting nut 45. The pull chain 46, which is usual in lamp sockets of this character for operating the switch, passes downward through a central hole 47 in the nipple. Thus the strain on the fixture, in operatin the chain 46, is applied centrally and-.axia ly of the fixture as a whole. The hole 47 also admits cool air to the chamber formed within shade 36 and bowl 41, the air heated by the lamp escap ing through vents 34 in shell 32 at the top.

At the upper edge of the bowl 41 is a seating ring 48, bent or flanged to form a stop 49 holding the upper edge of bowl 41 in position, and a stop 50 to hold thelower edge of shade 36 in position. This checks any relative lateral movement between the edges of 36 and 41.

The dust shade 36 is preferably made of plain glass to permit the direct rays from the lamp to pass through. The bowl or shade 41 is preferably made of glass, whose inner surface is roughened to diffuse the 3 The lyoke 42, and consequently the bowl 1 or shade 41, may be adjusted up and down by the nut 30, and may be held in adjusted position on nipple 27 by a set screw, thus enabling the bowl 41 to be set up firmly against the check ring 48 and lower edge of the shade 36.

The shade 12 may be made of opaque, or translucent, or partially translucent ma# terial, and in any event will reflect light reaching it from the lamp L downwardly in a concentrated zone below the fixture. If the shade is translucent the light rays will in part pass through the shade, producing in a limited degree a general diffusion of light throughout the room, and in part bo reflected ldownward from its under surface in a concentrated area. The shade 12 is preferably curved downward at its margin so as to reflect rays from the light L 1nwardly toward the axis of the fixture, thus insuri a strong concentration of light immediate y below the fixture, as indicated in the lines radiating from the lamp (Fig. 1) representing light rays.

When the shade 12 is adjusted to its lowermost position as shown in full lines in Fig. 1, no direct rays'will pass to the upper part of the room, unless through shade 12, above the plane indicated by line a. When the shade -is raisedto dotted line position 12', a more general diffusion of light throughout the apartment is obtained, the zone of direct light being as high as line b. In this position of the shade a much less strong downward concentration of light re Hected from shade 12 will result,and a wider distribution of light throughout the room, whereas with the shade in its lower position of adjustment all the rays in angle c will be reflected downward by the shade instead of passing unobstructed to the upper part of the room. By adjusting the shade 12 at any of the intermediate points between its two extreme positions a varied distribution of light may be effected at the will of the operator.

I claim:

L In a lighting fixture, a stem, a lamp secured at the bottom of said stem, a downwardly reflecting shade above said lamp, a shade supporting shell surrounding said stem, an exteriorly screw threaded member on said stem, and an interiorly screw threaded member secured to the interior of said shell, by which the shell may be adjusted lengthwise on said stem, and means wholly interior to the shell for supporting the shade.

2. In a lighting fixture, a stem, a lamp secured at the bottom of said stem, a downwardly reflecting shade above said lamp, a shade supporting shell surrounding said stem, means for adjusting said shell lengthwise on said stem, and a heat deflector above the lamp extending across the bottom opening of said shell.

3. In a lighting fixture, a stem, a light source secured at the end of said stem, a cover holder secured to said stem, an upper dust cover supported by said holder, a lower bowl which together with said dust cover incloses said light source, said bowl having a central aperture in its bottom, means to support said bowl, and a flexible light controlling member extending downward through said aperture.

4. In a lighting fixture, a stem, a light source secured at the end of said stem, a cover holder secured to said stem, an upper dust cover supported by said holder, a

lower bowl which together with said dust cover lncloses said light source, and a frame comprising a series of ribs, interior to said cover and bowl, secured to sald stem, em-

bracing said light source, and supporting said bowl.

5. In a lighting fixture, a light source, an upper dust cover and a lowr bowl-like shade, together forming a cl''ed housing surrounding said light souce,vmeans to suport said cover and shade with their edges juxtaposed, and a seating ring between said edges adapted to prevent relative movement therebetween.

6. In a lighting fixture, a light source, an upper dust cover and a lower bowl-like shade, together forming a closed housing surrounding said light source, means to sup-- secured thereto, a `shade supporting shell adjustable on said stem, a top shade carried by said adjustable shell, a dust cover and a kholder therefor iixedly secured to said stem between the adjustable shell and the lamp, a lower bowl-like shade, a frame for supporting said bowl-like shade located'inside of the dust cover and bowl and connected to the end of said stem, vents atthe top of said dust cover and the bottom of said bowl, and a heat deflector between said dust cover holder and said adjustable shell.

9. In a lighting fixture, a shade supporting shell having an inwardly turned lip, a shade having an outwardly turned lip, two supporting rings one engaging and secured within the lip of the shell and the other engaging and secured exteriorly to the lip of the shade, and mutually interlocking means on said rings by which the shade may be removably supported by the shell.

10. In a lighting fixture, a shade support, a shade, and a pair of rings secured respectively to said shade support and shade, one ring having a series of apertures and the other a series of corresponding projections, whereby said rings may be mutually interlocked.

11. In a lighting fixture, a shade support, a shade, andV a pair of rings secured respectively to said shade support and shade, one ring having a series of apertures and the.

other a series of corresponding projections,

whereby said rings may be mutually interlocked, and stops at the sides of said apertures adapted to prevent the accidental dislodgment of said projections through said 5 apertures.

12. In a lighting fixture, a shade support, a shade, and a pair of rings secured respectively to said shade 'support and shade, one ring having a series of apertures and the 10 other a series of corresponding projections,

whereby said rings may be mutually interlocked, and stops at the sides of said apertures adapted to prevent the accidental dislodgment of said projections through said 15 apertures, the projection at one side of each aperture being longer than the other.

13. In a lighting fixture, a shade, a shade support carrying a supporting flange having a series of apertures therethrough, a flanged ring with a series of projections in th( flange corresponding to said apertures detachably connected to the shade, and stop: at the sides of said apertures adapted t1 prevent the accidental dislodgment of sai( projections through said aperture.

Signed by me at Boston, Massachusetts this fifteenth day of June 1915.

DAVID CROWN FIELD. Witnesses:

ROBERT CUSHMAN, CHARLES D. WOODBERRY. 

